Colorado's big transit experiment offers free fares in August

• In addition, the state's Bustang service is cutting fares by half through Sept. 5.

Of note: The program intends to alleviate ground-level ozone pollution created by car and industrial exhaust in the hot summer sun. Colorado's worst months are June through August.

Why it matters: Transit advocates say it's the largest zero-fare transit program in the nation, with the agencies involved averaging 5.8 million trips a month.

Yes, but: Whether the program will boost ridership — and convert people permanently to transit — is a major question mark.

• The outlook is particularly gloomy for the Regional Transit District, which covers seven metro counties. RTD is in the middle of a controversial overhaul that will focus on transit routes in Denver and not the suburbs. Boulder, which pays into the service, is already protesting the move.

Our thought bubble: The high ticket prices for RTD light rail trips to the airport typically make it cheaper for a Denver-area family to drive and park.

• Now, with free fares, the light rail may finally be worth it.